1. Field of the Invention
This invention generally relates to mechanisms for scoring sheet material and more particularly to mechanisms for precisely producing intermittent, uniform score lines in the surface of a moving sheet of material.
2. Description of the Prior Art
In the manufacture of flat glass such as by the float process wherein a continuous ribbon of glass is produced, it is desirable to cut the cooled glass ribbon into sections of desired block sizes by a continuous operation in which the glass ribbon is both longitudinally and transversely scored; an example of such a scoring arrangement being shown in U.S. Pat. No. 3,439,849 issued on Apr. 22, 1969. In such a scoring arrangement, it is extremely important that the longitudinal score lines begin and end precisely at the location of the transverse score lines since, if they do not precisely intersect, curved corners may be formed when the scored sections of the glass ribbon are subsequently broken. For architectural glass cut to finished sizes, in particular, such corners are unacceptable.
The scoring tools normally employed in the above-described arrangement, particularly those producing longitudinally extending score lines, usually include a scoring wheel disposed between a pair of longitudinally aligned free running wheels which move into and out of engagement with the surface of the glass ribbon such as shown, for example, in U.S. Pat. No. 3,742,793, issued on July 3, 1973. Conventionally, such scoring tools are mounted on brackets or tracks for movement across the glass surface in such manners and in such positions that the glass ribbon will be both longitudinally and transversely scored as the glass ribbon moves therebeneath. Many attempts have been made to provide scoring mechanisms having a fast response wherein uniform longitudinal score lines precisely intersect the transverse score lines to form a square corner. However, since the means for moving the scoring tools also have had to move the above-described gauge wheels, such mechanisms have had a relatively slow response and the intersections of the longitudinal and transverse score lines have been irregular, thus resulting in curved corners when the sections are subsequently broken along these lines.